When discussing the Mk 18 / CQBR program, we can divide the history and discussion in to two distinct categories: 1) The weapon system itself / upper receiver supplied and 2) the group of accessories deployed on said weapon systems (SOPMOD).

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Mk 18 Mod 0 / CQBR

The M4 carbine and M16 are not ideally suited for all missions, so it was proposed that the modularity of the M16 series would allow a user to replace the upper receiver of an existing weapon with one more suitable to the task. One of two proposed special mission receivers that were planned for inclusion into the SOPMOD Block II kit, the CQBR has taken off on its own. Like the proposed Special Purpose Receiver, the Close Quarters Battle Receiver has been more or less taken on by the Naval Surface Warfare Center, Crane Division (often referred to as NSWC-Crane or just "Crane") as its own project following the CQBR's removal from the SOPMOD program. Just as the Special Purpose Receiver morphed into the Special Purpose Rifle, and was type-classified as Mk 12 Mod 0/1, the complete CQBR-equipped carbine has been type-classified as the Mk 18 Mod 0.

The purpose of the CQBR remains to provide operators with a weapon of submachine gun size, but firing a rifle cartridge, for scenarios such as VIP protection, urban warfare, and other close quarters battle (CQB) situations. The CQBR is designed to provide improvement over previous AR-15/M16-type weapons in this category. The CQBR is usually issued as a complete weapon system, and not just an upper receiver. The CQBR was once only available to Naval Special Warfare units, but the Mk 18 Mod 0 has become general issue for Visit, Board, Search, and Seizure (VBSS) missions and, as of 2006, for NCIS agents deploying to active combat zones.[citation needed] The Mk 18 is also used by the Coast Guard's Tactical Law Enforcement Teams, Maritime Safety and Security Teams, and Maritime Security Response Team and the United States Navy's Explosive Ordnance Disposal (EOD) Operators.

Wikipedia has a good article with sources on the original CQBR/Mk 18 Mod 0 and its development.

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SOPMOD

The SOPMOD Program Management Office at NSWC Crane, IN, provides standardized, versatile weapons accessories to meet needs across SOF mission scenarios. These accessories increase operator survivability and lethality by enhanced weapon performance, target acquisition, signature suppression, and fire control.

The CQBR itself was originally part of the SOPMOD program as an accessory replacement upper receiver for the M4. However it was eventually separated out into its own project.

SOPMOD accessories for the M4/CQBR originally included things like the KAC RIS/RAS, SOPMOD stock, KAC M4QD suppressor, AN/PEQ-2 illuminator/laser, ECOS-N red dot, ACOG, etc

The SOPMOD program has gone through multiple minor and major evolutions throughout its lifetime. The most significant is commonly defined as "Block II" and included the introduction/replacement of accessories that met the updated needs of operators. The most visually significant "Block II" accessory is probably the replacement of the KAC rail/FSB with the  Daniel Defense RIS II free float rail with low-profile gas block. Other updates include things like the Surefire SOCOM sound suppressor, EOTech RDS (553/SU-231 & EXPS 3-0/SU-231a), LA-5/PEQ ATPIAL, etc

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Link to docs and photo albums

 Presentation on CQBR from Crane
 Operator's Manual for Mk 18 Mod 0
 SOPMOD Program Overview presentation from Crane
 Photo Album of Mk 18 Mod 0
 Photo Album of CQBR with SOPMOD Block II accessories

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Because of the long history of both the CQBR/Mk 18 and SOPMOD programs, it's common to find weapons with various mixed configurations in the field, all depending on what time and unit the weapon system belongs to. Below are a few examples with descriptions to illustrate this.


Example of a Mk 18 Mod 0 in as-issued configuration including: M16A1 surplus lower receiver, SOPMOD buttstock, KAC RIS, KAC M4QD flash hider, Aimpoint Comp M2 in Wilcox mount, LMT rear fixed sight, CQD rear sling plate.


NSW Operator CQBRs with original SOPMOD accessories including KAC M4QD sound suppressor and AN/PEQ-2 IR Illuminator/Laser.


Member of a Combat Camera team with a CQBR with KAC RAS and M4QD flash hider but with other updated accessories from the "Block II" SOPMOD kit including SU-231a (EOTech EXPS 3-0), EOTech G33 Magnifier, LA-5/PEQ ATPIAL, Insight WMX-200.


Good example of "early" CQBR with SOPMOD Block II accessories including SU-231 (EOTech 553) and SU-233 (Insight M3x weaponlight).


Example of a more "modern" CQBR with SOPMOD Block II accessories including the updated SU-231a (EOTech EXPS 3-0) and Insight WMX-200 weaponlight.


Many times certain configurations are common within certain branches/groups. Here a Marine Raider is seen with a CQBR with an AN/PEQ-16 (USMC issued vs. the LA-5/PEQ SOCOM issued ATPIAL) and KAC NT4 suppressor (vs. the current Surefire SOCOM suppressor).

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Building a clone

If you're interested in building a "clone" of a Mk 18 or CQBR equipped M4A1, here is a basic parts list to use as a guide and get you started. This list is not exhaustive and see the * note above regarding personalized accessories.

                       | Mk 18 Mod 0                      | M4A1 CQBR Block I                   | M4A1 CQBR Block II                                      
Lower Receiver         | Mil-spec forged A1               | Mil-spec forged A2                  | Mil-spec forged A2                                      
Stock                  | Gen 1 SOPMOD (Black)             | M4, CAR, SOPMOD, CTR & others       | M4, CAR, SOPMOD, CTR & others                            
Pistol Grip            | A1                               | A2, ERGO & others                   | A2, ERGO & others                                        
Rear Sling Plate       | CQD                              | CQD                                 | CQD                                                      
Upper Receiver         | Mil-spec forged M4 profile       | Mil-spec forged M4 profile          | Mil-spec forged M4 profile                              
Barrel                 | 10.3"                            | 10.3"                               | 10.3"                                                    
Rail                   | KAC RIS                          | KAC RAS                             | DD Mk18 RIS II (FDE)                                    
Rear BUIS              | LMT Fixed                        | LMT Fixed, MATECH, & others         | MATECH, KAC 300m, & others                              
Front Sight            | A2 FSB                           | A2 FSB                              | KAC 99051 BUIS (Taupe)                                  
Front Sling Attachment | FSB Sling Swivel                 | FSB Sling Swivel                    | CQD                                                      
Muzzle Device          | KAC M4QD                         | KAC M4QD                            | SureFire FH-556-RC                                      
Supressor              | None                             | KAC QDSS NT4                        | SureFire SOCOM556-RC (FDE)                              
LAM                    | None                             | PEQ-2                               | LA-5                                                    
Weaponlight            | SureFire M962                    | SureFire M952, M962                 | Insight M3X (Tan), Insight WMX200 (Bronze)              
Optic                  | Aimpoint Comp M2 in Wilcox Mount | Aimpoint Comp M2 in QRP Mount, ACOG | EOTech 553 (Tan), EOTech EXPS3-0 (Tan), ELCAN 1-4x (FDE)

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Link to previous threads

 Previous Mk 18 / CQBR Thread Part I
 Previous Mk 18 / CQBR Thread Part II

I don't have a dog in the fight, but I love cqbr's and if it means keeping a clone thread going, I'm all for it.

 

Pic thread:

Wild pic:


my contribution, awaiting RC can in a couple of months:

A little Mod 0 & Block I love:

US Navy SEALs

I don't get it. Isn't this what the other thread was?

Yep.

Placeholder

The other thread went down the toilet because some people have a very "accepting" view of what a "clone" or "variant" is.

Some more Mod 0 love



And some "CLONE" family pics

Your paint jobs are so well done. My favorite that I've ever seen by far. Awesome work.

Oh goody

Thanks.  It actually was a lot of fun to do.  Wishing I had taken pics when I painted them though.  There are also a lot of other really nicely painted rifles that I've recently seen here.  How many paint their Block II CQBR?  Any painted in the wild?

Operative word:  was.

Postal remissioned the thread; this is now the Mk18/CQBR thread.

That's quite a family you have there!

I'm doing all I can to r-e-s-i-s-t Mk12 disease.

I guess I will go ahead and get mine in here,

" />

 

In on one! Pics coming in a few.
 

















 

Thank you for keeping the thread going! I have read every page of both incarnations of the other thread and found it to be an invaluable resource. I will be finishing mine next month and I know I would've waisted a lot of money on the wrong parts without this resource, thanks again you guys!

It is interesting to see that on the uppers Colt is making that the side sling swivels are pointing forwards.  I know the Army specs this now, but I didn't know Colt was shipping uppers that way.

Now whos gonna mod this thread and keep the rifraf out

Excellent page 1.

Should read:

• Barrel: 10.3 Colt Government profile with .70 gas port
• Rail: Knights Armament M4 RIS
• Muzzle Device: Knights Armament NT4 Flash Hider
• Front Sight: A2 FSP
• Rear Sight: LMT
• Optic: Aimpoint CompM2
• Optic Mount: Wilcox
• Stock: LMT SOPMOD Gen 1 Black
• Grip: A1
• Light: Surefire M952
• Laser: none on Mk18 Mod0
• Supressor: Knights Armament NT4

Updated the errors, thanks!

You sure about the PEQ-2 though? I thought for sure I've seen quite a few in the wild Mod 0s with PEQ-2s.

The KAC rail panels or si6miliar could not be installed via sliding on the RAS on the left side with the sling mount installed as designed...so the mount has to go backwards for the swivel to fold out of the way properly...

Hrm. You can slide them on from the rear, I do it all the time :) The hand guard catch is a little in the way, but not too much.

On the mk18 probably not...the mk18 was used Navy and Coast Guard for VBSS...ship searching....and a complete rifle with surplus a1 lowers

CQBR uppers most like had the peq-2 etc...they are  pretty  much the same upper as the mk18, but just the upper was shipped to US ARMY and NAVY SPEC OPS to supplement their M4A1s as needed.

also a cut down carry handle is an OK BUIS for a CQBR upper....

You can scratch the delta ring from the rear...

schaz42 ,The A2 Grip was / is used on the MK18MOD0 also .

Placeholder.

Great paint jobs! Can you give us a rundown of what you did? Techniques, colors etc?


 

In addition to peq 2's add the peq5 visible laser.  When you study the MK 18's of Murph and Axe, they are using them since the peq 2 was IR only.  Also, I have a pic a fella running a DBAL.

I mentioned this in the other thread, but we're going to re-start this thread, I think there needs to be a consensus, maybe with starting another thread to discuss the issue of what is and is not a clone.  

Once we can come to a general agreement on what is and is not, it needs to be displayed prominently at the beginning of the OP with a statement about what is or is not going to be considered acceptable.  

Beyond that, the most I can do is perhaps ask that everyone refrain from the "doesn't belong here" comments if something out of place is posted, and simply hit the "Report" button - once we have a working definition clearly posted, all a Mod needs to do reference the reported photograph/build with the definition and decide whether to nuke it or not.  

Then again, that might end up sucking for the Mods, still wouldn't prevent those who disagree with the definition from spamming the thread, and no matter what, it'd be unfortunate to see these threads have to be so carefully moderated and bound by so many rules and become less enjoyable in some ways, but I don't know what the best solution would be... these threads have become too large, it appears, for them to police themselves...

I don't think a separate "clone forum" is the right answer, either.  

::sigh::

It's a shame it came to this.

~Augee

I've been wanting to do this for a while now, but finally decided to make it happen today...

I'd like to find that rear BUIS!

Is the rear a KAC in FDE?  (that's what my uneducated guess is)
Also,,,,,,,,,the frt sight in that pic...........what is it?   and it's blk.

M961 for your mod 0 list :)  classic pics

weat966, is that a SF X300 on the side of the DD M4A1 rail ?

If you're building a rifle, and attempting to replicate a build you saw "in the wild", then yeah, post it up! It'd be great to even see posts where both the "in the wild" pic and the build pic are posted together so people can see what you're going for.

I'm not sure there's any hard specific rules we could create that would work. To me it makes more sense to just keep things to a "reasonableness" test.

Ultimately I think that there's just a good group of people who are interested in these rifles/receivers and the history that goes along with them. Seems to make sense to have a thread dedicated to photos, information, discussion, and clone builds.

Now on to the bad news…

Finally got around to replacing my Noveske 10.5 with a Colt 10.3 on my Block II CQBR. Aaaaand… it doesn't run :( Short stroking. I purchased the barrel in the EE thinking it was a factory 10.3 but now I'm wondering if it's been cut down from a 14.5 or 16. My Noveske barrel ran about everything I threw at it, so really disappointed.